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Re: Lobo floppy drives

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  • s100doctor
    ... I think the 25229 sounds like a Shugart 800/801 board model number. ... the DJ2D-B is a decent enough 8-inch controller. Morrow docs are good. The
    Message 1 of 40 , Nov 15, 2012
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      --- In midatlanticretro@yahoogroups.com, Richard Cini <rich.cini@...> wrote:
      >
      > Bill --
      >
      > I didn't have time to pull both drives tonight but I did unmount the
      > left-hand drive. Indeed it's a Shugart 801, SN# HV2633. As far as jumpers,
      > DS1, T1, X, B and A are closed. EZ is set to Z. EI jumper is open. The
      > 800/801 jumper is also open. There are black-ink markings on the PCB as
      > follows: "25229.1", "1932", "48.2". I'll try to pull the other drive
      > tomorrow and let you know if it's any different jumper-wise (assuming it's
      > set for DS2).

      I think the 25229 sounds like a Shugart 800/801 board model number.
      >
      > On a slightly-related note, I have two floppy controllers, a Morrow DJ2B and
      > a VersaFloppy II, that I would consider using to build a new floppy system
      > from. Is one better than the other for these drives? The Morrow board looks
      > like 8"-only while the VF2 has both floppy connector types.
      >
      > Rich

      the DJ2D-B is a decent enough 8-inch controller. Morrow docs are good.

      The Versafloppy II is also a decent controller. My Web site has work of half a dozen people with that controller, including John Monahan (s100computers.com).

      http://www.retrotechnology.com/herbs_stuff/s_sd_vfii.html

      Either ought to be able to run those Shugart 800's.

      Herb Johnson
    • Mike Loewen
      ... Here s the service manual for the Tandom TM-848, with the schematics in the back: http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdf
      Message 40 of 40 , Dec 15, 2012
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        On Sat, 15 Dec 2012, joshbensadon wrote:

        > --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@...> wrote:
        >>
        >> The double-sided drives have a 2S signal on pin 10 of the interface
        >> connector to indicate single or double-sided media. The outputs of the
        >> respective pulse-shaping ciruitry for each sensor is essentially ORed to
        >> form a single Index pulse output.
        >
        >
        > Cool, so I can imagine the two sensor signals going to an RS flip flop
        > to provide the 2S signal and as you said to an OR gate for the index.

        Here's the service manual for the Tandom TM-848, with the schematics in
        the back:

        http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdf

        Knock yourself out. :-)

        > Hmm, thinking about why, I guess the design was to create a hardware
        > error if a user placed a DS disk into a SS drive. As Rich found, the
        > lack of index pulses caused a drive not ready. Correct me if I'm wrong,
        > but in later 5.25" drives, they did not change the index sensor
        > location. Then I suppose the errors created would be software
        > generated?

        The 5.25" drives only had a single index hole aperture.

        > I vaguely remember hearing a discussion about how computers switched
        > from hardware solutions to software solutions, then back to hardware.
        > I just don't know the dates, could this 8" to 5.25" be part of that
        > switch?

        I couldn't say. Certainly Woz did a lot in software for his Apple II
        disk controller design. Another odd thing about the 8" drivers vs the
        5-1/4" drives was that the 8" drives had a write-enable notch, while the
        5-1/4: drives had a write-protect notch. Very confusing.


        Mike Loewen mloewen@...
        Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
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